Di-p-isobutyl sebacate



Patented July 9, 1946 George Kesslin, New York,'and LeonardNicholl,

Nyack, N. Y., assignors to'Kay-Fries Chemicals, Inc., West Haver tion of New York straw, N; Y., a corpora- No Drawing. Application necember 2, 1943,

Serial No. 512,638

3Claims. ((31. 2 0485) This invention relates to a novel chemical compound di-p-isobutyl sebacate, the method of making same, and to elastomer in which it is incorporated as a plasticizer.

In the present day accelerated development of synthetic rubber plastic compounds, or, more properly speaking, elastomers, there has been a crying need for plasticizers which will impart to the elastomers a desired low temperature flexibility. In the use of synthetic rubbers for equipment in polar region under sub-arctic conditions, as well as for industrial uses in refrigeration and low temperature work generally, it has been found that elastomers or synthetic rubbers are not plasticized or flexibilized properly, to stand under low temperature working conditions. This is particularly true with the general run of plasticizers used for rubber and rubber substitutes. In the development of the newer elastomers, including those of the butadiene-acrylonitrile types, frangibility at low temperatures is very marked. This condition has .been overcome by incorporating therewith a suitable plasticizer, such as di-p-isobutyl sebacate recently prepared and discovered by us. This to approximately 99 C. In a practical operation, at this temperature, a constant boiling mixture of p-isobutyl alcohol and water forms and begins to distillover. A sufiicient quantity of the constant boiling mixture is distilled over to remove all the water. At this stage of the process the liquid temperature in the still will have reached 133 C. and the vapor temperature approximately 97 C. 100% esterification of the acid by the alcohol is indicated when a test sample on titration requires approximately .8 cc. of N/lO NaOH per 1 cc. of sample. The crude ester product is then treated with 7.8 lbs. of anhydrous sodium carbonate (100% excess for the indicated acidity). The crude product is then distilled without a dephlegmator and under a low vacuum of 140 mm. to remove residual primary isobutyl alcohol. Thereafter the di-pisobutyl sebacate is distilled over, preferably under a high vacuum of 2 mm. to 4 mm. with corresponding variations in liquid temperature. Generally, the more the pressure used approaches atmospheric pressure, the higher the distillation temperature Will have to be.

A typical distillation run is as follows:

[Total weight of batch- 805 lbs.]

Acidity Liq. Vap. We1ght Ester Fract. temp temp Press. tract as 32135010 Remarks Degrees Degrees Mm. Pounds Percent Percent l 78-145 -60 -2 132 .2 Practically pure isobutyl alcohol. 2 154 2 41 98. 8 .081 Good produ t. 3 154 164 2 575 99. 2 081 D0. 4.. 51.6 Residue.

compound may be incorporated in varying The reaction described above can be graphamounts in an elastomer of the butadieneacrylonitrile type, although in amounts varying from 10 to 25% of the elastomer it has been found to give excellent results, particularly the much desired low temperature flexibility now so highly sought after. I

The novel compound Oi the present invention may be prepared in the following manner: 670 lbs. of p-isobutyl alcohol are charged into a gallon still. The liquid is raised to a temperature of approximately 80 C. and while stirring,

435 lbs. of 97.5% sebacic acid are added as rapidly as convenient, and usually in a one to two hour time period. To the mixture in the still there is added 3.8 lbsfiof concentrated sulphuric acid as a catalyst, and the still is closed. The temperature of the reaction mixture is increased until the liquid temperature has risen ically illustrated by the following equation:

It will be appreciated that there has been provided a novel compound di-p-isobutyl sebacate, particularly suited as a plasticizer for elastomers of the butadiene-acrylonitrile typ and particularly adapted to impart low temperature flexibility to them and other elastomers.

What is claimed is:

l. Di-p-isobutyl sebacate.

2. The method of preparing di-p-isobutyl sebacate, comprising esterifying =p-isobutyl alcohol and seb'acie acid in the presence of sulphuric acid as a catalyst, the p-isobutyl alcohol being in substantial excess, heating to 99 C. to complete the reaction and form a constant boiling mixture of p-isobutyl alcohol and water and distilling ofi same during the course of the reaction, leaving the newly formed di-p-isobutyl sebacate dissolved in anhydrous residual primary isobutyl alcohol, neutralizing the reaction mixture with anhydrous sodium carbonate, then distilling under low vacuum to remove residual primary isobutyl alcohol followed by distillation at high vacuum to secure pure dl-p-isobutyl sebacate.

' treated product under a low vacuum of 140 mm.

to remove primary isobutyl alcohol, and then under a high vacuum of 2 mm. to distill off the pure di-p-isobutyl sebacate.

' GEORGE KESSLIN.

LEONARD NICHOLL. 

